[Updated model, 1/14/2014, with better balance - a little sanding of the tail surface may still be required.]
A jumping dolphin with a curved body. Once printed, it can stand on its nose and tail, or upright just on its tail (may require a little bit of support/putty magic).
Blender file included for any improvements you might want to make (model is rigged with bones along the spine for you to play with!).
Original 3DS model from: http://www.3dmodelfree.com/models/26530-0.htm
(Has been modified, rigged to curve the dolphin.)
Printed on MakerBot Replicator 2 with ReplicatorG at 0.27mm layer height with raft and full support. Regular version STL is about 9cm long head to tail, takes about an hour to print; "large" version is about 13.5cm, takes a little over 2 hours (same geometry, just scaled).